v0.3.1 : Bugfixes and small improvements.

Added

• Error raise if geomagnetic field is invalid in class EKF.
• New method Omega in class AQUA to simplify the product between angular rate and quaternion.
• New method rotate_by in class QuaternionArray.
• More Acronyms in page Nomeclature of documentation.
• Individual pages for each method and attribute of classes Quaternion and DCM into documentation.
• Merge pull request of basic automation tests.

Changed

• Fix undefined matrix R in method update of class EKF.
• Fix shape of converted points in function ned2enu.
• Fix parameters in function rec2geo of submodule frames.
• Fix method from_quaternion of class DCM.
• Fix Munich height (in km) in global constants.
• Improve detection of empty arrays when building TRIAD object.
• Improve description of estimator AQUA in its docstring.
• Improve imports in submodules frames and dcm.
• Improve style and descriptions in docstrings of functions in submodule orientation.
• Method init_q is now synonym of the more convenient method estimate in class AQUA.
• Parameter as_quaternion in method estimate of class TRIAD renamed to representation, and its value is now of type str.
• Versioning is defined using f-strings.

Removed

• Redundant normalization of magnetic measurement vector in class FQA.